Pressure accumulator



y 1 51 l. E WEBER ETAL 2,550,892

' PRESSURE ACCUMULATOR Filed Jan. 26; 1944 INVENTORS [5041' 5 5 2 4 61 Jam/t B/umm/a/r /7 TTOIPNE) Patented May 1, 1951 PRES SURE ACCUMULATOR Isaac E. Weber, New Rochelle, and Joseph Blumenfeld, New York, N. Y., assignors,.by direct and mesne assignments, to Simone Mercier,

New York, N. Y.

Application January 26, 1944, Serial No. 519,782

1 Claim. 1

This invention relates to pressure accumulators. Pressure accumulators are used for supplying fluid under pressure to various machines. Thus, they are used for supplying water, oil, or other liquid or a gas under pressure to hydraulic presses or gasoline to certain airplane motors. The principle upon which the accumulators function is the compression of a supply of fluid against a buffer of air or other fluid, so that as one fluid is withdrawn during use, the buffer fluid, usually gas, expands and thus makes possible the delivery of a substantial quantity of the fluid before the buffer falls in pressure to the minimum pressure allowable upon the fluid being withdrawn.

The class of accumulators to which the present invention relates is that in which a flexible bag contains, for example, a buffer gas and a liquid containing compartment surrounds the bag. The accumulator is provided with a valve or other means for introducing gas within the bag and a port through which the liquid is pumped during the stage of accumulating a supply of the liquid under pressure and through which the liquid is withdrawn during its use.

In accumulators of this type there have arisen difiiculties due to the closing of the outlet port or ports before all of the liquid ata pressure above that required can be withdrawn, injury to the expansible bag by contact with the device for closing the main liquid port or with other rough part of 5 the apparatus, and inconvenience of obtaining access to the inside of the accumulator when it is desired to, remove, repair or adjust inner parts of the assembly.

The present invention comprises a pressure accumulator having a plug with an annular passage or a plurality of primary liquid passagewaysin communication with the main port for liquid, the said plug being of such shape of surface, on theside adjacent to the buffer gas bag, as to be non-conforming with the outer surface of the bag. As a result of this non-conformance of shape, the bag as it expands on withdrawal of the accumulated liquid under pressure, closes the primary passageways serially and does not close the last of them .until the liquid that is to be delivered has passed substantially completely through them.

The flexible bag, when no stress is exerted inwardly upon it, has a shape similar to the inside of the shell, allowance being made for the protuberance formed by the plug with a clearance between the bag and the shell of 2 mm. or so in which space a soft cushion of oil may be trapped.

The said cushion of oil enables the bag when unfolding to take its developed form with a minimum of friction on the shell wall.

While unfolding the bag must not close the oil ports but must leave open an exit for the oil. After several months of operation the bag, then slightly deformed, may trap some oil in places more or less distant from the oil ports; when, however, all the oil surrounding the oil ports is expelled the pressure in the bag becomes greater than the pressure of the surrounding oil. The bag then would tend to take a spheroidal shape, but the plug prevents it from doing so and the bag, pressing hard on the plug, receives a corresponding reaction which tends to push it in the general direction opposite to the plug.

As the oil ports are preferably situated in recesses, it will be seen that the previously trapped oil is expelled through the'oil ports. Thus the invention solves the problem of the expulsion of the maximum possible amount of oil with a minimum stress and fatigue of the bag.

The invention will be illustrated by detailed description in connection with the attached drawing in which the single figure is a sectional view of the accumulator of the present invention.

' Referring now to the drawing, the pressure accumulator comprises a container or pressure chamber III preferably of strong rigid material such as steel, cast aluminum or the like, capable of withstanding high pressure. The container may be spherical of cylindro-spherical as desired and has a collapsible and expansible bag H3 therein which preferably is of resilient material such as rubber or synthetic plastic of like physical characteristics and which in distended; but substantially unstretched condition is smaller than the cavity ofthe container. The container I H and the bag H3 define therebetweena space ll3fto receive thepressure accumulator liquid, the space I I3 becoming very large as the bladder is collapsed and the contained gas therein is compressed by liquid forced through the opening I24 in closure plug I23.

Thus, if the pressure upon the gas in ba 3 is made 1500 pounds per square inch by pumping liquid into the space H3, andthe volume of the gas in bag H3 is reduced to approximately of .the volume of the'ga at, normal atmospheric pressure, the volume of such 'space'll3 for'r'eceiving the liquid forced therein is increased by an amount corresponding to the compression and. decrease of volume of the gas in the bag H3.

The closure plug I23 comprises a bottom plate I23 having an upstanding rim l3l at the periphery thereof and unitary therewith and a concave cover plate I25 is seated on an annular shoulder I32 in the inner wall of said rim HI and rigidly afiixed thereto. A portion of rim I3I extends above said cover plate to form an upstanding member or flange I29 which will be more fully described hereinafter.

A plurality of passageways I23 are provided in cover plate I2 5 preferably disposed from the center to the edge thereof, and a plurality of lateral radiating ports I27 extend through said rim I3I. from the interior of the container I I I to the liquid receiving and holding space I33 between the bottom plate I23 and cover plate I25.

Closure plug I23 has a peripheral groove I34 therein beneath ports I 27 and arubber gasket I22: preferably afiixed to said rim beneath said groove. A snap ring I2I is seated on. the beveled edge I35 of opening II2 of the container against shoulder I36 thereof and in groove I34 in the rim I34 of the plug and a peripheral slot I31 is provided at o the end of rim: I3-I. below bottom plate I23 extending outside the container to accommodate a snap-ringi28, thus securely to retain the closure plug in the container.

' The bag I I3 is securedin the container as by means of a flange II5- rigid with the nipple IIB, the latter extending through the air inlet port of the container, and secured thereto by means of a nut I28 screwed on the threadedv end. of the nipple, a. washer II 9 intervening between the nut and the rim 8' of. the container providing. a liquid andair tightseal. 7 In the assembly of the device shown in Fig. 6, the rubber bag. H3 is first inserted through the opening II2. Closure plug I23 is then inserted into opening H2 and snap ring I2I is fitted into peripheral groove I34 in the rim of the closure plug and then seated on the bevelled portion I35 against shoulder I36. Snap ring. I28 is then inserted into peripheral. slot I31 securely to retain the closure plug in place. To use the device shownand described herein, a fluid, preferably air, is forced under pressure into the inlet H6 leading into therubber bag I I3 until the desired pres-sure, which may be of the order of. 1.500 pounds per square inch or more, is attained. This will: cause the rubber bag M3 to stretch and snugly engage the inner wall of the container. The inlet. i then sealed by any suitable valve (not shown). oil, is then forced under pressure into outlet or port I24 of the container to fill the latter.

The. liquid compresses the gasv in the rubber bag thus: decreasing its volume, and as. the liquid is generally forced into? the container until a very high. pressure is obtained, illustratively of. the order oi 5000 pounds per square inch, the rubber bag will be collapsed.

As the accumulator approaches exhaustion of liquid. and the rubber bag becomes stretched and stifi, it reaction against the upstanding member or flange I29v protruding inside: the container will force the bag against the pole of the container substantially opposite the. upstanding member. The further expansion of the stretched and stiffened' bag during. continued discharge of. liquid from the container will result in a higher reaction pressure. of the bag against the wall area of the container opposed to said upstanding member A liquid, preferably an than against the intervening wall areas of the container.

Thus, during such expansion of the rubber bag with the expulsion of liquid from the container, as the pressure of thebag against the wall of the container becomes progressively less toward the outlet, if any liquid should remain between the rubber bag and the container wall it would tend to be squeezed from the area of maximum pressure to the area of lesser pressure. This would preventv any liquid from being trapped between the wall of the container and the rubber bag.

Whenthe rubber bag expands to the position shown in solid lines it contacts flange I29 of closure plug I23 and cuts off openings I26 from communication with the container. However, lateral portsv I27- will still remain open. Further expansion of the rubber bag to the position shown in dot and dash lines will force any liquid remaining on the plate I25 through the openings I26 therein andalsoseal the ports I27. With this construction substantially all the space in the container is utilized and all the available liquid therein is forced out.

It will be understood also that it is intended to cover allchanges and modifications of the example of the invention herein chosen for the purpose of illustration which do not constitute departures from the spirit and scope of the inventi'on.-

What is claimed is:

In a pressure accumulator of the class containing a collapsible bag holding a buffer gas and a pressure vessel surrounding the bag and defining therewith a space to receive and hold fluid under pressure; the combination in which the pressure Vessel has a closure plug with an outlet port, said plug having a flange spacing the collapsible bag wall from the pressure vessel, a perforatedplate surrounded by said flange and bores through said flange communicating to the port from. the space intervening between the pressure vessel and the collapsible bag.

ISAAC E. WEBER. JOSEPH BLUMENFELD.

REFERENCES CITED The: following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 20,887 Mercier Oct. 18, 1938 594,039 Serve Nov. 23, 1897 2,132,952 Hewitt 1 Oct. 11., 1938 2,256,835 Mercier Sept. 23, 1941 2,267,121 McMullen et a1. Dec. 23', 1941 2,273,457 Zimmerman Feb. 17, 1942 2,283,439 Herman May 19, 1942 2,324,701 Herman July 20, 1943 2,331,921 Mercier Oct. 19, 1943 2,342,356 Mercier Feb. 22, 1944 2,347,379 Teeter Apr. 25, 1944 2,349,321 White May 23, 1944 2,385,016- Mercier Sept. 18, 1945 2,390,319 Overbeke Dec. 4, 1945 2,390,320 Overbeke Dec. 4, 1945 2,399,444 Mercier Apr. 30, 1946 

